Probably that many places have pursued policies of preventing forest fires entirely when they are actually a natural part of ecological development. If you keep preventing forest fires, you end up with a lot more potential fuel buildup than if you let them burn once in a while.

I'm sure someone will point out that CA does controlled burns on occasion, but it's not the same thing.

Edit: here's some reading on the topic: https://www.npr.org/2018/09/27/649649316/fire-ecologists-say...

Not OP but I think this is what he/she may be referring to: https://99percentinvisible.org/episode/built-to-burn/

The article is good. But podcast itself is also good.

Shoulda raked our woods like them Finns.